A stereological study on the neuroprotective actions of acute Modafinil treatment on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigral lesions of the male black mouse

The effect of an acute administration of the vigilance-promoting drug modaf inil ((+/-)(diphenyl-methyl)-sulfinyl-2 acetamide; Modiodal) on the nigrost riatal dopamine system was studied after damage induced by MPTP (1-methyl-4 -phenyl-1,2,3,6-tetrahydropyridine) by means of immunohistochemistry for ty rosine hydroxylase (TH) and a stereological method. MPTP (40 mg/kg) reduced from 24 380 +/- 902 to 13 501 +/- 522 and from 37 868 +/- 3300 to 20 568 /- 1270, respectively, the number of TH immunoreactive (IR) and non-TH IR n igral neurons. Go-administration of Modafinil restored to normal the number of these neuronal populations. MPTP treatment induced also a reduction in the volume of TH IR neurons, which was counteracted by Modafinil administra tion. The data provide morphological evidence, based on unbiased stereologi cal analysis, for a potential neuroprotective role of Modafinil, not only i n dopaminergic neurons, but also with a similar magnitude in the non-DA ner ve cell population of the substantia nigra after MPTP lesion. These results suggest that Modafinil has a neuroprotective role in the substantia nigra via a still undefined mechanism in which a crucial role of DA uptake blocka de should be excluded. Modafinil may therefore have a therapeutic potential in neurodegenerative processes such as those occurring in Parkinson's dise ase. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.